Signals which contain several component signals are conventionally analyzed component-signal by component-signal by measuring devices. For this purpose, a device under test is usually supplied with an excitation signal, and a resulting test signal is mixed in an analog manner with a local oscillator signal to form an intermediate-frequency signal. This signal is then limited by analog filtering to the frequency range relevant for a first component signal. The resulting narrow-band test signal is now digitized and further processed. Following this, the same process is repeated for further component signals, which are contained in the original signal. Accordingly, EP 1 592 131 A1 discloses a measuring device which contains the above-named procedure. The disadvantage here is that the component signals cannot be investigated simultaneously. In particular, in the case of base stations which broadcast signals of different communications standards, for example, GSM, UMTS, LTE, simultaneously, interactions between the individual component signals cannot be investigated in an adequate manner with conventional measuring devices.
Accordingly, there is a need for a measuring device and a measuring method which can measure signals composed of several component signals.